Manual hydraulic pumps are used in many applications in the field where electrical or other power operated pumps are not practical or economical. One such usage is in the installation of shoring which is the support structure which holds the sides of trenches during construction. The support structure consists of vertical support rails connected together by horizontal cylinders into which fluid, usually water mixed with a soluble oil or other lubricating fluid, is pumped until a desired pressure is reached, to press the vertical rails against the sides of the trench. A series of these support rail structures may be placed along the length of the trench. Each rail support structure must be individually filled with fluid and brought to a pressure to properly press against the sides of the trench to hold it in place and prevent its collapse.
This filling of the horizontal cylinders to the proper pressure is now most often done by a single cylinder manual pump submerged in a container of fluid. A quick connect coupling attaches a hose from the output of the pump to the horizontal cylinder. The pump handle is then pumped to bring the fluid. from the container into the horizontal cylinder. Until the horizontal cylinder is filled with fluid the manual pumping is quite easy. However, when the vertical rails make contact with the trench walls, the manual pumping becomes very difficult. A pressure of from 700 up to about 6000 psi, or higher, may be required, depending upon the nature of the soil, to properly put the shoring in place. It may be very difficult, for one individual to pump the fluid to the pressure required. A need exists for a pump which allows an individual operator to easily fill the fluid in the shoring to the required pressure using a small manual pump which fits into the container of fluid which is to be pumped into the shoring structure.